New methods for the Preparation of Nitrosyl Chloride

A pure sample of nitrosyl chloride has been prepared either by reaction of phosphorus trichloride with concentrated nitric acid or by reaction of phosphorus trichloride with sodium nitrate in presence of water. The nitrosyl chloride gas has been characterized by i.r. spectral data and elemental analysis.     

Decomposition of silane on solid P4O10

Silane undergoes thermal decomposition on the surface of “phosphorus pentoxide” ( P₄O₁₀) into its elements around 200–400°C. The hydrogen formed partially reduces the P₄O₁₀ forming lower oxides of phosphorus and water. Elemental silicon is precipitated as reddish-brown solid, which is separated by dissolving out the phosphorus oxides. Silica and disiloxane are not formed in the reaction.     

Photophysical Studies on the Interaction of Acridinedione Dyes with Universal Protein Denaturant: Guanidine Hydrochloride

Photophysical studies of photoinduced electron transfer (PET) and non-PET based acridinedione dyes with guanidine hydrochloride (GuHCl) were carried out in water and methanol. Addition of GuHCl to photoinduced electron transfer (PET) based acridinedione dye (ADR 1) results in a fluorescence enhancement, whereas a non-PET based dye (ADR 2) shows no significant change in the fluorescence intensity and lifetime. Addition of GuHCl to ADR 1 dye in methanol results in single exponential decay behaviour, on the contrary a biexponential decay pattern was observed on the addition of GuHCl in water. Absorption and emission spectral studies of ADR 1 dye interaction with GuHCl reveals that the dye molecule is not in the protonated form in aqueous GuHCl solution, and the dye is confined to two distinguishable microenvironment in the aqueous phase. A large variation in the microenvironment around the dye molecule is created on the addition of GuHCl and this was ascertained by time-resolved area normalized emission spectroscopy (TRANES) and time-resolved emission spectroscopy (TRES). The dye molecule prefers to reside in the hydrophobic microenvironment, rather in the hydrophilic aqueous phase is well emphasized by time-resolved fluorescence lifetime studies. The mechanism of fluorescence enhancement of ADR 1 dye by GuHCl is attributed to the suppression of the PET process occuring through space.     

Hydration, swelling, interlayer structure, and hydrogen bonding in organolayered double hydroxides: insights from molecular dynamics simulation of citrate-intercalated hydrotalcite

Molecular dynamics (MD) simulation of the Mg/Al (3:1) layered double hydroxide (LDH), hydrotalcite (HT), containing citrate, C6H5O7(3-), as the charge balancing interlayer anion provides new molecular scale insight into the interlayer structure, hydrogen bonding, and energetics of the hydration and consequent swelling of LDH compounds containing organic and biomolecules. Citrate-HT exhibits affinity for water up to very high hydration levels, in contrast to the preferred low hydration states of most LDHs intercalated with small, inorganic anions. This result is consistent with the recent experimental observation of the delamination of lactate-HT. The high water affinity is rationalized in terms of the preference of citrate ion for hydrogen bonds (H-bonds) donated from water molecules rather than from the hydroxyl groups of the metal hydroxide layer and the need to develop an integrated interlayer H-bond network among the citrate ions, water, and -OH groups of the hydroxide layers. The changes in the orientation of citrate molecules with progressive hydration are also intimately related to its preference to accept hydrogen bonds from water.     

On the repetitive operation of a self-switched transversely excited atmosphere CO<Subscript>2</Subscript> laser

The repetition rate capability of self-switched transversely excited atmosphere (TEA) CO₂ laser was studied for different gas flow configurations. For an optimized gas flow configuration, repetitive operation was achieved at a much smaller gas replenishment factor between two successive pulses when compared with repetitive systems energized by conventional pulsers.     

Ab initio and DFT benchmark study for the calculations of isotopic shifts of fundamental frequencies for 2,3-dihydropyran

Structural Chemistry - A systematic investigation has been carried out to assess the performance of various exchange–correlation energy density functionals coupled with various basis sets to...     

Growth of highly oriented crystalline polyaniline films by self-organization

Silicon substrates with (100) orientation were modified with amino-silane self-assembled monolayer (SAM) to provide amino (NH(2)) moieties at the substrate surface. Self-organization of polyaniline during chemical polymerization, on this modified surface, leads to the growth of highly oriented films at the substrate-polymer interface. The morphology studied using scanning electron microscopy and atomic force microscopy revealed the formation of polymer film with well faceted pyramidal crystallites. XPS and FTIR spectroscopy were used to analyze the chemical structure of the film. X-ray diffraction measurements show the crystalline nature of the polyaniline, whose lattice parameters are in agreement with the reported values. This study underlines the importance of a SAM in deciding the structure and morphology of the deposited polymer.     

A regioselective 1,3‐dipolar cycloaddition of 2‐arylidene‐1‐tetralones with DPNI

Synthesis of a series of novel 1,3‐diphe nyl‐4‐arylspiropyrazolines[5.2¹]‐1¹‐tetralones has been accomplished in good yield by regioselective 1,3‐dipolar cycloaddition of diphenylnitrilimine with (E)‐2‐arylidene‐1‐tetralones. X‐ray crystal structure analysis of one of the products 4b confirms the structure and the regiochemistry of cycloaddition. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 331–336, 1999     

Synthesis, spectroscopic, redox, catalytic and antimicrobial properties of some ruthenium(II) Schiff base complexes

A new series of mixed ligand semicarbazone or thiosemicarbazone complexes of Ru(II) having the general formula [RuCO(EPh₃)(B)L] (where E = P or As; B = PPh₃, AsPh₃ or Pyridine; L = dibasic tridentate ligand derived by the condensation of ethylacetoacetate/methylacetoacetate and thiosemicarbazide/semicarbazide) have been synthesized and characterized by physico-chemical, spectroscopic and electrochemical studies. A comparative study on the catalysis of oxidation of benzyl alcohol, cyclohexanol, cinnamyl alcohol, n-butanol, n-propanol and iso-butyl alcohol has been done with N-methylmorpholine-N-oxide and molecular oxygen as co-oxidants. Catalytic activity studies of the complexes in coupling reactions have been carried out. The antibacterial properties of the complexes have also been examined.